Over a period of time the weight of racing vehicles has been reduced and engine horsepower increased. With reduced weight and increased engine power, transmissions with three or more forward gear ratios are not required, and transmissions have been modified to reduce the number of forward gear ratios.
The modified transmissions conventionally have two forward gears and one reverse gear and have improved the performance of racing vehicles. However, these modified transmissions have several objectionable characteristics. For example, their cases are larger and heavier than is required. A countershaft is driven constantly, thereby not only consuming power, but also churning the lubricant and heating the entire transmission assembly. The inertia due to the rotating parts is excessive and impedes both acceleration and deceleration.
Several proposals have been made to overcome the disadvantages described. For example, the engine flywheel has been eliminated from the drive train thereby decreasing inertia and improving acceleration as well as deceleration. However, removal of the flywheel also eliminated the starter ring gear that generally was mounted on the periphery of the flywheel.
Clutches have been added to eliminate rotation of the countershaft gearing when the transmission is shifted into direct drive. These clutches have limited useful lives, may cause lubricant leaks, and require major disassembly of the entire transmission when replacement is required.
Elimination of the flywheel and the starter ring gear precludes the use of conventional engine starting systems. In one proposal the engine starting system is provided by connecting a ring gear carrier plate to a starter, like that used in combination with a torque converter, in lieu of the flywheel. A conventional starter has a drive gear that engages the ring gear to start the engine. The added ring gear carrier and an attached ring gear become, in effect a lightweight flywheel that rotates whenever the engine is running, thereby resulting in undesirable drive train inertia.